The present invention relates to a ship for treating a coal slurry to transport the coal slurry as loaded in its own holds or to load the slurry into the holds of another ship.
Generally coal is transported by land from coal mining areas to loading ports, where it is loaded into ships for transport by sea. To reduce the cost of transport by land and also to assure an efficient loading operation at the port, is it frequently practice in recent years to disperse pulverized coal in water in the mining area to obtain a coal slurry, transport the coal slurry to the port through a pipeline and thereafter load the slurry into a ship also through a pipeline. This method is very advantageous in that coal can be automatically loaded into the ship with use of a floating hose or the like which is supported by a buoy and connected to a facility on the shore without mooring the ship alongside a wharf. However, the usual coal slurry to be loaded into ships by pipelines contains, for example, about 50 to 70% by weight of water, so that the coal slurry is inefficient to transport as it is and requires a prohibitively high transport cost since the amount of coal that can be loaded into the ship is smaller by an amount corresponding to the water content. To enable the ship to transport coal with an improved efficiency, it is required to drain the coal slurry to the greatest possible extent and thereby load the ship with as much coal as possible. Further as an increasing amount of coal is loaded into the hold, coal particles settle, permitting a portion of the slurry water to collect above the mass of coal particles. Accordingly if the ship rolls while transporting the coal slurry in this state, the overlying portion of slurry water heaves to pose the hazard of pronounced rolling or is likely to strike against the hatch cover or flow out from the hold. Such a problem similarly arises also when the ship rolls during loading. The slurry water collecting above the mass of coal particles during loading must therefore be discharged as promptly as possible in order to eliminate the above objection and to assure an efficient slurry loading operation.
With conventional coal slurry transport ships, the coal slurry is directly transported into the hold and dewatered through drain outlets equipped with a filter and provided in the bottom of the hold, but it is difficult to efficiently discharge the slurry water from the bottom drain outlets. Thus there is the problem that such ships are low in coal slurry loading efficiency.